Green Industry Resources
Hort Update- Seasonal Information for the Green Industry
Show Questions -- July 5, 2012
1. We have six questions about Japanese beetles and most of them are from Omaha. They're eating everything from peaches, nectarines, apples, pears, and lindens. People knock them off with water streams, but they come back. What are we recommending for the infestation of Japanese beetles this year?
a. We can sound negative because the reality is there's so many of them---they keep coming and coming and coming and then, finally, they outlive their adult stage toward the mid to the end of July. We have several more weeks. You can still find some in early August. The main thing is, if you have fruits and vegetables, they're difficult to treat because your only option is just a contact type of insecticide such as the permethrin products. Carbaryl is a good one for Japanese beetles. You need to be able to treat the aggregation of the beetles that are feeding. And then you must make sure you observe any harvest interval between when you treat and when you eat the vegetables. They're easier to control on ornamentals (on trees and shrubs) than in the garden setting. Very difficult. Some people put out yellow or white buckets of soapy water to see if they're attracted to that and manually trying to get rid of the masses. It's just something that we need to develop sort of a tense truce with. Because they're just going to be here and they're going to be more and more numerous and spreading across Nebraska.
You don’t need to cut down the host species or anything like that. Plant more than you need when it comes to herbaceous types of things.
2. A viewer had a neighbor who had a mature cottonwood. The tree went down, but now there are suckers coming up all over the lawn. Cottonwood suckers are showing up and wants to know what to do.
a. If that tree is gone, some of the root tissue might still be living but eventually it will die. They can do a couple of things. They can continue to mow them off and eventually the suckers will probably stop growing up or they can use a product like Finale which will burn off any of them that come up. Be persistent and it will take care of itself.
3. We have questions about tomatoes and potatoes. The viewer sent some pictures. One tomato planted in the middle of the rest, looks pretty sick and the ones on the either side look healthy. They're from from Waco.
a. This might be a couple of things. Can't tell for sure what the other tomato plants looks like. This plant looks stunted. There's a stunting virus. Where it is just one plant in the planting, I would really suggest removing this plant right away to get the inoculum source out of the garden. That's the best thing you can do.
4. This viewer just planted 3 foot tall Colorado spruce trees; so, late June it sounds like. They have clay soil and want to know good watering practices for those new trees.
a. These were probably dug and balled and burlapped, which is the most common type of planting. You lose a lot of roots when a tree is dug up, and balled and burlapped. They need some good watering to get through the hot temperatures. Soak them down really well once a week until we're back into the 70s and 80s and then you could probably go to one good watering every 10 days to two weeks. But, really soak them down well and aim to moisten the top eight to ten inches of soil. You're putting a lot of water on. And do that once a week to get them through the really hot weather.
5. Jim, you have the first picture. This is a Blair viewer. They have three full grown burning bushes. Planting these was done twenty-two years ago. One burning bush leafed out and started to do things incorrectly. And it has sort of borer issues and curling foliage, and the bark is sloughing, and they want to know what they should do with this plant. Is there any hope for it?
a. It looks so serious, I don't think there is any hope. The plant itself is so old. The crown area is probably not as vigorous as it used to be. And so it's had a lot of injuries and damage over the years, and I think it ought to be replaced. If you like the burning bush, replace with a newer one. I think you'll find out that it will glow a lot more vigorously and eventually fill in in area.
6. This viewer a zoyzia lawn that has patches looking dry, flat, and decaying. Any management issues associated with zoyzia? It's a 30 year old lawn.
a. I don't know of any off of the top of my head. It's usually a fairly hardy grass. Other than looking for something like compaction---or it's been extremely dry and it's been a year that has really been bizarre so far. Other than looking at some of the environmental conditions that might be going on there, it's kind of tough to tell, especially without a picture on that.
Loren: If it is a patch, there's a large patch disease of zoyzia that we see that's related to brown patch. And it could be that if it's a circular patch. They may want to bring in a sample of it to Extension or testing lab.
Jim: I suppose it could be chinch bugs. If it's a single circular thing, conceivably it could be spreading. I think there would be more of it around. It's worth a check. The leaves are often indicators. They're reddish when they suck in the stems of the crown area you get reddish flagging on the leaves. That's a good indicator. So that's probably a possibility too.
7. Turfgrass diseases. Apparently there are rusts that are everywhere.
a. Turfgrass rusts: I brought along a sample that we can show of rust. There is, the turf diseases are just going very well right now, and rust is one of those. I think this blade may work pretty well. If you can see the actual blade there's little orange spots. With the turf rust, you get dust on your shoes, hopefully it's not to that point yet, and this is actually pretty early for rust. It's probably been in the area for three weeks now from what I’ve seen developing on some of the landscapes. There are fungicides that you can use. Rust is a good indicator of turf being in low fertility though. I would really look at your fertility program and how much notrogen you're putting on and step that up when we get into the fall. Look at how much nitrogen you're putting on. And if you really want to control it, you need to use a fungicide. The systemic lawn fungicides will do a good job with that. There are a couple things to consider with spraying and the weather. When it’s 100 degrees, spraying anything is a bad idea. Make those applications in the evening if you do make those applications or early in the morning.
8. A viewer in Kennard has a 45 year old pin oak. The leaves are light green. They are in clay soil. They have given them iron treatments but it doesn't seem to be working. They're not really seeing the dark in the veins. Any notion on what might be going on with that?
a. I still think it's iron chlorosis. You don't always get the dark discoloration of the leaves until the case is so severe what you're starting to get twig and branch dieback. Depending on what kind of treatments you've done---trunk injection is the most direct treatment and has fastest effect and that's best done in the spring, as the new growth is emerging. If you did an injection now, you probably wouldn't see much effect until next year. There's other ways to go about it. There's a publication online from the Nebraska Forest service called "Treating Iron Chlorosis in Eastern Nebraska" that talks about soil treatment methods with sulphur and a combination of products where you drill holes in the ground. Take a look for that on the Nebraska Forest Service website. But an injection is usually the quickest way to go about treating that.
9. This is an Omaha viewer, Jim. They have mud daubers. They're scary looking. They are making mounds in the ground. There are more and more of them each year.
a. I think they're cicada killers. They just started and will be around for three or four weeks. They're not aggressive. That's what is really nice about them. While they're busy and trying to attract each other and mate and look for cicadas, they're not necessarily aggressive to you unless you start to swipe one and land on one or whatever. I hope that's a consolation. That means you can tolerate them. If it's really essential that you try to control them or something, I would try to adjust somehow the area where they are building their mounds. Keep it moist. It's really hot out, but try to keep it moist so it's difficult to dig in. If you want to cover it with something---hardware cloth, temporarily, or nylon cloth---to make it difficult to dig. Or mulch the area if you think it would be suitable to do that. Or you can put down a granular insecticide to discourage their presence there. Generally, try to appreciate the activity for what it's worth and be assured that they're not aggressive.
10. Lowell you get the next picture. The viewer has a white thistle, pure white, and they are wondering if they can take the seeds and grow it again.
a. It's not the greatest idea in the world. A number of thistles are noxious weeds in the state. I can't exactly tell which one that is from the picture. Sometimes you see these oddities. If they did take the seeds, more than likely it's a recessive gene that causes that. There's no guarantee that they would get more thistles with white blooms on them or anything like that. Because it's a thistle, we would not recommend taking seed from it.
11. Lauren, a viewer has a 30 year old short-needled pine; on the west side, it's browning from the top down. There are almost no needles that are green on the west side. Is this disease-based from something in the crown?
a. I’ll comment and if Sarah wants to add in, she may have things too. Short-needle pine that is dead on a large portion of the crown makes me think of the possibility of pine wilt. Many times it will affect the portion of the crown of the tree. So I would watch it carefully. It doesn't sound like a foliar disease, it's across the top, it would typically be in one part. I don't have a recommendation for doing in that, but you would watch the tree carefully and suspect pine wilt.
Sarah: I would completely agree. I think it's probably pine wilt too. If they wait another two or three weeks, the whole tree will probably be brown and they know it is pine wilt and they can rogue it out.
12. This viewer has several cucumbers; they are in the sun until 4:00 p.m. The plants are vining like crazy and sound like the oriental type (the long ones). They are not getting any cucumbers. It’s the same variety as last year. A neighbor bought plants and is getting cucumbers but it's a different variety.
a. It's probably pollination issues related to heat. With the temperatures as high have they have been, the pollen doesn't transfer well to the flowers and there is no fruit set. There can be cultivator differences. Some types of plants may pollinate better under hot conditions and others may not. I think you'll need to wait out the weather until it gets cooler and hopefully you see more cucumbers setting on.
13. Jim, a Bellevue viewer has a question about a black insect, smaller than a fly, bigger than a gnat. They make a black smear when killed. They want to know what they are. Any idea without a picture?
a. I think an image would be best. I don't even see a setting being described here. There's a lot of small, blackish insects. Sorry about that. Pictures or detailed information.
14. We have questions from western Nebraska where the hot and dry is deadly. Ogallala and Alliance viewers have bluegrass and they want to know how much water to apply to keep it from dying. How long can bluegrass go without water of any sort without croaking?
a. The bluegrass will go dormant during the hot times of the year. If you want to keep it green, we like to water it deep and infrequent unless it's a special type of situation where the turf is injured or something like that and needs special maintenance. Unless the turf is injured. But if when you walk on the grass, you can see footprints, and it's a bluish color, irrigate a good amount, an inch or so, and do that as needed on that. That's probably the best approach. Basically, kind of let the grass tell you when it needs to be watered instead of sticking to a regimented schedule.
15. Loren, we have had an awful lot of questions about lilies and daylilies with diseases. We have yet another one about a person who thinks they've found the disease down in the crown of the plant. They wondered do they really need to dig the whole thing up and throw it away or is there hope for rescue.
a. A few things on daylilies that we see. Bacterial soft rots and there are some fungal root and crown rots that we see with older plants. Really in those cases, many times the bacterial diseases we talk about discarding the plant, but you can try to cure the plant or help it and remove the effected areas. If we look at some of the management options on that, you can dig up the plants, cut away the effected material, let it dry out in the shade or something, and then replant that. You can also just remove that soft rot to try to reduce the inoculum that way. And when we get into the crown rot, you want to dig those plants up. I don't know that I with do that now, I would wait until it's cooler to do transplanting but take the material not affected and clean it up.
16. Sarah, you get the next picture, and quite a beautiful one. A viewer that went on one of the habitat tours and they saw a plant that they don't recognize and wonder if we can give them a name.
a. This another plant that grows from a bulb. It's called crocosmia. This is a cultivar called 'Lucifer' that has red flowers. The more common type of crocosmia has orange or yellow flowers. It's hardy in Nebraska so you can leave it in the ground and It will perform nicely year to year. They're striking when in full bloom.
17. We have a whole bunch of questions about bagworms. They are on the usual things, from baldcypress to junipers, the usual suspects.
a. We're surprised by this. It seems like with the recent bagworm reports that we have, the worms are quite small. We usually find them earlier. While they're still small it's a great opportunity to treat them because they're more vulnerable to insecticide applications. You can use Bacillus thuringiensis or spinosad, those are two of what we would call biorational types of products that you can use. And you can also use permethrin, carbaryl, or bifenthrin depending on what it's on. Watch the label directions. The main thing is get enough on that there, get enough coverage so they ingest it and it's soaked into their bags and it kills them. Do it now. Don't wait too long. You never know just how many you have. They get bigger and you realize that you should have done something two or three weeks ago.
18. A peach tree has a good amount of fruit set, but it is being destroyed by small black beetles.
a. I see some things on the outside of the fruit. It looks like a brown rot disease that we see on stone fruits. In the center, there's not really anything more that will affect the seed cavity if it's a disease. It may just be poor seed development.
Jim: It looks really clean. It could have been breached by some insect in an early stage and some fungus got in there. Those little black bugs are probably picnic/sap beetles. They recognize that that fruit is spoiling and they are attracted to it.
19. This is a viewer with a three-stemmed peach that is loaded with fruit. One branch has split and they're wondering if the can screw it back together again and end up with a healthy tree. If not, it is there a variety that we might recommend for that part of Nebraska?
a. It wouldn't be a good idea to screw them together because that's not a sustainable way for trees to grow. We see this happen with peaches and apricots with the heavy fruit. You might get the tree to limp along to get the harvest. It's probably a good idea to let the tree go or prune off the split branch and work with what is left that's viable. With peaches in Nebraska, you need to worry about winter hardiness. Early blooming ones tend to have frost problems with the flowers dying. So we would look at cultivars like 'Reliance' or 'Red Haven' or 'Madison'; those are all good peaches for Nebraska.
20. Here’s a Japanese beetle follow-up question. They bought a Japanese beetle bag, filled it up, and emptied it. And now they're filling it up again. They wanted to know where they could find another bag and do they really work?
a. They actually do work. They have a pheromone and a floral lure. It smells like roses and the beetles are attracted to it. They're not good fliers so they hit the fins on the the device and fall into the bag below. The bags can fill up pretty quickly with Japanese beetles. Some local garden centers and hardware stores might sell the bags but you can buy them online. Keep in mind, in an isolated situation it might help cut down the population. If you have Japanese beetles in a neighborhood, everyone would need to cooperate with the same strategy to have an impact.
21. A Wahoo has algae in their pond; they want to know how fast does pond algae grow, how to control it, and is it harmful to pets?
a. I don't think that algae is harmful to pets. Right now, it's difficult to do anything about the algae. A lot of the effective treatments have to be applied to the water prior to the algae forming and growing. Some of the treatments escape me at the moment; but in our guide to weed management, we do have a full page of options for aquatic weed control. But we're a little bit late in the year to be really effective in controlling a lot of the water weeds.
Sarah: To find out if you have harmful blue green algae, the School of Natural Resources has a lab where you can send in water samples. You can find the information on their website.
22. This next question is about wilt on eggplant.
a. If you look at the picture, the lower leaves are yellowing; that's usually what our root rot type diseases like verticillium do. It could be fusarium wilt as well. It is in the soil. If the plant is really struggling, you can remove it. That does not preclude the other plants from getting the disease. In the future, I would try looking at resistance. You may want to send in a sample to get it identified to make sure it's verticillium wilt so you know what to do with your ground in the future.
23. Two cherry tree questions: 1) five to six feet tall tree the leaves are beginning to turn yellow and are curling up and 2) three year old dwarf cherry with yellowing leaves and some are falling off.
a. We have seen a lot of trees this year losing some of their initial foliage. They put on a lot of foliage when things were cool. The extended hot, dry weather we are seeing has caused some trees to shed foliage. You don't see specific spots on the leaves or a pattern, so it's probably environmental. The viewer might need to do additional watering on the trees. The leaf drop may not stop, but hopefully you can prevent any additional die back. If you can see spots on the leaves, there are some fungal diseases there, too.
Loren: You can look online for cherry leaf spot and other types of spot that we see on cherries.
24. Here is a question from a Broken Bow viewer about black beetles on the kitchen wall. They are a quarter of an inch long and are in two segments. What should she do?
a. They could be related to something that was brought indoors or foodstuff/ stored food that has become infested. Check out your pantry. There are small weevils in old bird seed and in rice. Check it out and dispose of it.
25. How can they get rid of sumac coming up all over the place?
a. It depends on the setting it is in. They could use something like Tordon, but now is not the best time to do that. It would probably be better to treat it in fall or spring.
26. Here’s a question about cantaloupe with leaves curling and then dying but some of the fruit is good.
a. It could be bacterial wilt. You may want to send in a sample to get that confirmed.
1. Can garlic be left in the ground over winter?
a. Yes, you can plant in September, let it over-winter, and continue growth in the spring
2. How long does it take to go from the single clove to a garlic bulb?
a. If it is planted in September, you can harvest at the end of May or June.
3. We have a question about the best time to transplant rhubarb in Cherokee, Iowa.
a. I would wait until September.
4. Is there worry about the depth?
a. You want the crown just under the soil line, but don’t want to bury it too deep. Put them at the same level they were before if they did well.
5. We have questions about large trees with hollow branches, jagged branches. Should they fill the holes?
a. You never fill the holes. It will never stop the wood rot. It's a little bit subjective. That question is a bit hard to answer simply. But if more than 50% of the circumference of the branches are affected, I would say get rid of it.
1. Black spot is still showing up on roses. Should a fungicide be applied or is it too hot?
a. It can be applied but you need to do it in the evening or early morning. Avoid spraying in the heat of the day.
2. Viewers are calling about the lower leaves on their tomato plants curling. Is that viral?
a. There are several fungal diseases that typically affect the lower leaves first. They can remove the leaves to reduce the innoculum.
3. Is there any way to avoid hollyhock rust occurring next year if they have it this year?
a. There are resistant varieties or they could choose to not grow hollyhocks.
4. Are there diseases of asparagus that cause the plant to die from the top down?
a. Not that I know of. Bottom down is more of the fungal diseases we would see.
5. How about fescue lawns that go from green to mostly brown at the base overnight. Is that fungal?
a. That's no water.
6. What if there is fungus in pine bark mulch bag?
a. It shouldn't have any effect. There are many things that colonize the bark mulch. I would go ahead and use the mulch.
1. Will vinegar work to keep the weeds out of new pavers?
a. They can burn down existing foliage but it won’t stop new weeds from growing
2. To keep new weeds from growing, what can they do?
a. It's difficult to get a residual herbicide. The best bet is being persistent with a vinegar or Roundup type of herbicide.
3. A viewer in Broken Bow cut down chokecherry trees and they don't want any suckers.
a. Chokecherries sucker up a great deal. Keeping at the suckers is just what they need to do; there’s no way around it.
4. What product type and timing should be used for henbit control?
a. 2,4-D is very good. The liquid spray product is fine. You’ll have to watch for it. There should be little seedlings in the lawn. They can be difficult to see, but as soon as they see them, they are germinating and then you need to apply the 2,4-D.
1. What is the maximum temperature for insecticide application? Is there a maximum above which you shouldn't do it?
a. If it is within the vicinity of 90 degrees, it probably means that the weather conditions are not conducive for insecticide applications. Cool is good.
2. We have lots of viewers that have caterpillars on tomatoes. What are they and how can they be controlled?
a. They are probably tomato fruit worm, tomato hornworm, or tobacco hornworm. If they're small, use BT, if they're large, pick them off.
3. How can you prevent hollyhock stalk borer?
a. In mid May into June, treat the base of the plant with a dust application of an insecticide to keep them from finding the stem. You try to create a barrier or insecticide there.
4. Here’s a question about one-inch long brown worms. What are they and how do you control them?
a. I think they are probably like millipedes. We're getting migrations now because of the hot weather kicking them into survival mode and they have to have cool and moist conditions. So masses of them will move in around the home and into the landscape.